Obituary of Glenn M. Frye

Glenn M. Frye, professor of physics emeritus at Case Western Reserve University, died on 8 January 2007 at the age of 80. His research interests at Case centered on the detection and identification of cosmic rays at the top of the atmosphere.

Glenn was born in Ithaca, Michigan in 1926. He completed both his undergraduate and graduate studies at the University of Michigan. After earning his doctorate in 1950, he joined the nuclear physics research staff at Los Alamos Scientific Laboratory. For much of his seven years at LASL, Frye used nuclear emulsion techniques to study the interactions of 10-20 MeV neutrons with light nuclei such as lithium and boron. Such measurements provided important information on the behavior of neutrons in reactors and weapons.

In 1958, Frye and his colleague Alice Armstrong exposed their emulsion stack to the negative external beam at the newly commissioned Bevatron proton accelerator at UC Berkeley. Their papers were among the very first to present evidence for the annihilation of antiprotons with nucleons in the emulsion.

Shortly afterward, Frye changed direction by joining with Fred Reines, who was also at LASL, in a cosmic ray experiment. In 1959, Reines moved east to become chair of the Case Institute of Technology physics department, and the following year he invited Frye to join him there. Glenn would chase after cosmic rays for the next 33 years.

The first years at Case Tech were devoted to the development of the rather complex spark chamber detectors which were destined to be suspended from high altitude balloons. Frye’s experiments would be carried by the winds for hundreds of miles at altitudes greater than thirty miles, in both the northern and southern hemispheres. The maiden flights were launched in 1965 from the Palestine, Texas National Center for Atmospheric Research Balloon Base. The object was to search for gammas in the 30 to 500 MeV range coming from discrete point sources. It would not be until three years later, that the Frye team, along with collaborators from the University of Melbourne, reported success in this search. In a later Texas flight, high energy gammas were observed to come from the direction of the Crab Nebula, and, much more significantly, they arrived in the correct one millisecond bin of the known thirty millisecond period of the responsible pulsar.

In later flights, involving ever more sophisticated detection schemes, Frye and his team collected valuable data on energetic gamma rays emitted by a dozen other sources. Through the 1970’s and 1980 s, they employed detectors with improved sensitivity and directionality to determine the energy distribution of cosmic gammas. With the participation of CWRU colleague Thomas Jenkins, the group undertook a series of experiments to determine the atmospheric gamma-ray spectrum from 50 MeV up to 12 GeV. The group subsequently developed spark chambers and time-of-flight electronics for the detection of neutrons from the sun and other sources. When opportunities for satellite-borne experiments became available, Frye and Jenkins joined in an experiment aboard the Compton Gamma-ray Observatory Satellite. Their particular interest was gammas and neutrons associated with a particularly large solar flare.

Until his retirement in 1993, Glenn Frye found a way to do exciting physics and astrophysics which involved travel and adventure, world-class research, and great opportunities for his students and colleagues. He brought international attention to the CWRU physics department, and was a pioneer in the astrophysics and cosmology program which continues at CWRU to this day.

William Fickinger and ,

Professors Emeriti, Physics Department, Case Western Reserve University